Effects of opaque, weighted bottles on maternal sensitivity and infant intake

Abstract

Caregivers' abilities to assess how much is in the bottle may lead to encouragement of infant bottle emptying and overfeeding. The present study assessed whether use of opaque, weighted bottles (as compared with conventional, clear bottles) improves feeding outcomes. Mothers with infants <32 weeks of age (n = 76) were assessed on two separate days. Mothers fed their infants from an opaque, weighted bottle on 1 day and a clear bottle on the other; conditions were counterbalanced. Blinded raters certified in the Nursing Child Assessment Feeding Scale scored all videos to determine maternal sensitivity. Infant intake was assessed by weighing the bottle before and after each feeding, and feeding outcomes included infant intake (mL), intake per kilogram body weight (mL/kg), meal duration (min), and feed rate (mL/min). Mothers exhibited significantly greater sensitivity (p = 0.041), fed their infants fewer millilitres per kilogram body weight (p = 0.049), and fed their infants at a significantly slower rate (p = 0.009) when using opaque compared with clear bottles. Infant clarity of cues was a significant moderator of effects of bottle type on intake per kilogram body weight (p = 0.028): Infants who exhibited greater clarity of cues were fed less during the opaque versus clear conditions whereas infants who exhibited poorer clarity of cues were fed similar amounts during both conditions. Effects of bottle type were not moderated by bottle contents (expressed breast milk vs. formula). In sum, promotion of opaque, weighted bottles for infant feeding may be a pragmatic approach to improve the quality and outcome of bottle-feeding interactions.

Keywords: bottle-feeding; infant feeding; infant-feeding behaviour; maternal sensitivity; overfeeding; responsive feeding.

Conflict of interest statement

The authors declare that they have no conflicts of interest.

© 2018 John Wiley & Sons Ltd.

Figures

Figure 1

Effects of bottle type on infant intake per kilogram body weight for infants with higher versus lower clarity of cues. To illustrate the significant interaction between bottle type and infant clarity of cues, this figure presents predicted values for infant intake per kilogram (kg) body weight for infants with lower (−1 SD below the mean) versus higher (+1 SD above the mean) clarity of cues. Infants with lower clarity of cues were fed similar amounts during the clear and opaque conditions. In contrast, infants with higher clarity of cues were fed significantly less during the opaque condition compared with the clear condition